In general, the dryer is an apparatus for drying a drying object, such as clothes introduced into a drum with hot air heated by an electric heater, a gas burner, or the like, of which demand keeps increasing, recently.
FIG. 1 illustrates a disassembled perspective view of a related art dryer.
Referring to FIG. 1, the related art drum 1 is provided inside of a cabinet (not shown) that forms an exterior of the dryer. The drum 1 is cylindrical with opened front and rear, having a belt groove 2 along an outside circumferential surface for winding a belt (not shown) connected to a motor or the like.
The drum 1 has a chamber 5 for holding the drying object therein, with a plurality of lifts 6 each projected a length from an inside circumferential surface of the chamber 5, for lifting/dropping the drying object during rotation of the drum 1, to turn the drying object upside down, for fast drying of the drying object.
The drum 1 is provided with a front supporter 7 and a rear supporter 9 to a front and a rear thereof, respectively. The front supporter 7 and the rear supporter 9 close as well as support the front and the rear of the chamber 5, respectively.
There are sealing member 10 between the front supporter 7/the rear supporter 9 and the drum 1 for preventing leakage of water. The front supporter 7 and the rear supporter 9 are provided with a plurality of rollers (not shown) in alignment with the front and the rear of the drum 1 for supporting the drum 1, respectively.
The front supporter 7 has an opening 8 for making the chamber 5 in communication with an outside of the chamber 5. The opening 8 is opened/closed by a door, selectively. The rear supporter 9 is provided with a supply duct 12 in communication with the chamber 5 as a passage for supplying hot air to the chamber 5.
There is an outlet assembly 13 at one side of the front supporter 7 under the opening 8 in the front supporter 7 as a passage for escaping of air from the chamber 5. The outlet assembly 13 has a filter 14 fitted thereto. The filter 14 removes foreign matters (for an example, thread wastes, or dust) from the air escaping from the chamber 5.
The outlet assembly 13 is in communication with an exhaust duct 15, having the filter 14 positioned at an inlet thereof. The exhaust duct 15 is connected to a fan housing 18 for flow of air from the chamber 5 to the exhaust duct 15 and the fan housing 18 as a fan 17 in the fan housing 18 comes into operation. It is preferable that the fan 5 is a centrifugal fan for effective use of a space, but an axial fan is also acceptable.
The fan housing 18 has one side in communication with the exhaust duct 15, and the other side connected to the exhaust pipe 19. According to this, air passed through the fan housing 18 is discharged to an outside through an exhaust pipe 19.
In the meantime, the supply duct has an inlet in communication with a guide funnel 16. The guide funnel 16 has a form of a truncated cone for guiding the hot air produced by burning the gas toward the inlet of the supply duct.
There is a gas burning device 20 provided to the inlet of the guide funnel 16. The gas burning device 20 is provided with a valve, a mixing tube, and an igniter. The valve, connected to a gas pipe, controls supply of gas. The mixing tube mixes the gas sprayed from the gas nozzle with the air, and the igniter ignites the mixed gas.
In the meantime, the drum applied to the dryer is fabricating by the following process in the related art.
Referring to FIG. 2, at first, thin metal plate of such as stainless steel is rolled into a cylinder and a seam thereof is welded. Next, a diameter of a middle part of the cylindrical drum is expanded, leaving both ends as they are. In this instance, the middle part of the drum is expanded as dies provided to an inside thereof press assigned areas of an inside circumferential surface of the drum, outwardly.
Then, beads are formed in the middle part of the expanded drum. That is, a plurality of thin grooves are form along an outside circumferential surface of the drum, for strengthening the drum. Also, front and rear edges of the drum are hemmed.
However, the related art method for fabricating the drum has the following problems.
In the related art method for fabricating a drum, the middle part of the drum is expanded by pressing the inside circumferential surface of the middle part of the drum with the dies. Therefore, after finishing fabrication of the drum, traces of the dies remain on the drum, resulting in a poor outer appearance. Also, as a circular shape of the drum is impaired, the drum fails to have uniform rotation inertia, to generate noise and vibration during rotating the drum.